Two top CIA officials have resigned amid reported disagreements with the new management of the US spying agency.

Deputy Director for operations Stephen Kappes and his assistant Michael Sulick were part of the CIA unit dealing with covert operations around the world.

The new CIA head Porter Goss said their departure would not affect the global fight against terrorism.

Mr Goss was appointed by President Bush in September to reform the agency after a series of intelligence failures.

The CIA (Central Intelligence Agency) was especially severely criticised for failures relating to the 11 September attacks in the US and also inaccurate reports on Iraq's alleged weapons of mass destruction (WMD).

Agency in turmoil

Mr Kappes and Mr Sulick - both CIA veterans with multiple overseas assignments - informed their colleagues that they were leaving the agency at a morning briefing on Monday.

Mr Goss later praised the two officers of the CIA's Directorate of Operations.

"The legacy that both officers leave behind them is one of dedication to the covert mission of this agency," Mr Goss said in a statement.

Serving CIA staff are banned from talking with the media, but former agency's officials have pointed out to intense internal friction with Mr Goss' arrival.

There is no doubt that Mr Goss is a man of strong views, the BBC's security correspondent Gordon Corera says.

Before he was nominated to run the CIA, Mr Goss made clear that he thought the agency had failed in its "core mission", our correspondent says.

Some CIA officers have already left, others seem likely to leave in the coming days and weeks, but what kind of agency emerges from the fallout - and whether it will be stronger and more effective - is something no-one yet knows, our correspondent says.